Unravelling the mysteries of expert mental calculation

Considering that the average adult cannot perform even the most elementary of mental calculations, the calculative feats of expert mental calculators seem unbelievable and mysterious. The processes and procedures which characterize expert mental calculation will be identified through a review of the published literature. In particular, it will be argued that experts can perform complex mental calculations because of their knowledge of a variety of calculative methods, their ability to recall instantly large numerical equivalents, and their ability to remember the numbers involved in the various stages of a calculation.